Switch actuating device



Jan. 22, 1957 Filed Oct. '7, 1955 THATCHER SWITCH ACTUATING DEVICE 2 Sheets-Sheet 1 SWITCH ACTUATIN G DEVICE L-e'wis Thatcher, Chicago, 111., assigu'or to Gaylord Products, Incorporated, Chicago, 111., "a corporation of Delaware This invent-ion relates to improvements in a device for actuating-an'elect-ric switch in response to the rotary. speed of a rotating body.

One of the important features of the .present invention resides in the-provision of a device which may be mounted upon a rotatable shaft or other rotatable body and which rotates with said shaft or body, the device being so contrived that, when said shaft or body is stationary or moves ata relatively low rotational speed, it assumes a predetermined position and when the shaft or body rotates above a predetermined minimum speed the device'assumes :a different position, an electric switch being associated with the device which is actuated by changed positions of .the device.

Briefly described, .the device comprises a-hollow annular member constructed of a resilient material, the annular member being mounted upon a rotatable body 'or shaft; the interior of the hollow member carries a relatively viscous fluid .and a disc, mounted upon the rotatable body or shaft, extends into-the fluid filled annular member. An electric switch is disposed exteriorly adjacent the annular member and carries a resiliently impelled actuating arm which "bears upon the annular member and tends to deform the annular member and cant the same relative to its axis of rotation. The arrangement is such .that'when the body or shaft is stationary or rotates at a relatively low speed, the switch actuating arm cants the annular member whereby the switch occupies a predetermincd position. However, when the rotary speed of the body or shaft exceeds a predetermined speed, the reaction of the disc within the annular member .upon the fluid within said member sets up a force upon said member which resists and overcomes the force of the switch actuating arm and, home, said actuating arm is moved, whereby the switch is actuated to a different position.

The objects and advantages of the present invention will be moreapparent from the accompanying drawings and following. detailed description.

In the drawings,

Fig. 1 is a longitudinal sectional view of a device embodying the concepts of the present invention, the device being stationary or rotating at below a predetermined minimum speed.

Fig. 2 is a view similar to 'Fig. 1 illustrating the position \of the device when rotating above the predetermined minimum speed.

Fig. 3 is a transverse sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a transverse sectional-view taken on line 4-4 of Fig. 2.

Fig. 5 is a longitudinal sectional view similar to Fig. 1 of a modification of the invention, the device being stationary or rotating below a predetermined minimum speed.

Fig. 6 is a view similar to .Fig. 5 illustrating the position of the device when rotating at a speed above said predetermined minimum speed.

United States Patent 0 "Ce 2,778,899 Patented Jan. 22, 1957 Fig. 7 is a transverse sectional view taken on line 7-7 'of'Fig. 6.

Fig. 8 is a transverse sectional view taken on line .-8--8 of Fig. 5.

Although a deviceembodyingthe-concepts of the present invention maybe used in many environmentsand for purposes of controlling substantially any type of operation in response to therotary 'speed of arotating body, for purposes of illustration, the rotating body from which the-control is exercised will be considered as the :speedometer cable of a conventional automobile speedometer. The operation controlled, in this case, may be a speed governor, an .anti-creep'device or the like.

Referring in detail to the drawings, .1 indicatesahousing which comprises-a cup-shaped member 2 and 31110511176 3. The bottom of the cup-shaped member 2 carries a boss 4 which extends downwardly fromsaid bottom and carries external threads 5. The closure 3 carries an upwardly extending boss 6 co-which an internally threaded coupling 7 may be secured, the periphery of the closure resting upon the upper edge of the walls of the cup threadedly connected .to boss 4-and coupling 7 and the speedometer cable itself (not shown) may be connected to opposite ends of the shaft 8. Thus, the devicel may be 'carriedby the speedometer cable sheath and theshaft 8 comprises an interposed connection in the speedometer cable, whereby when said cable is rotated, shaft 8 rotates therewith.

Within the :housing .1, the shaft 8 extends through spaced bosses 9 and 10, respectively carried by the memher '2 and closure 3'. A rotor 11 is carried by shaft 8 between said bosses.

The rotor 1'1 is constructed of a resilientmaterial and comprises two substantially symmetrical halves, 12 and 13. The half portion 12 comprises-a .hub portion 15 which is adapted to be imm'ovably mounted upon shaft 8 and the half portion '13 comprises a similar hub portion 16 similarly mounted upon said shaft. Extending radially outwardly from the hub portion 15, half. portion 12 comprises an annular dished or warped disc and a similar annular dished or warped disc extends outwardly from the hub portion 16. .Each of the dished discs carries :at its outer edge a beaded flange 17, the opposed beaded-flanges being clamped together by an annular C- sectioned clamping ring 18. When the opposed beaded flanges are thus clamped together the unitary rotor 11 is thus formed having a hollow annular interior space .hubs -15-and' 16. The disc 20 is annular and extends radially outwardly fromshaft 8 into the annular space 19.

-A liquid 2 1:fills the space .19 and, hence, the peripheral portion of the disc 20 is immersed in said liquid. The liquid 21 may comprise substantially any type of liquid but a silicone oil or grease is preferred since its viscosity changes very little with agitation and change in temperature. As will behereinafter described, the viscosity of the liquid 21 is an important factor in the operation of the device.

-A ring-22 is pivoted-upon diametrically oppositely disposed journals 23 which are mounted upon the side wall of the member 2. The ring 22 circumscribes the rotor 11 and is spaced radially outwardly from the outer periphery of the rotor. U-shaped clevises 24 are mounted upon opposite sides of the ring '22 and the arms of said clevises loosely embrace the annular clamp 18. The arrangement is such that rotor 11 is free to rotate within ring 22, the annular clamp 18 sliding through said clevises. However, rocking movement of the rotor about an axis transverse to shaft 8 isconstrained by ring 22, that is, rocking movement of the rotor can only take place about the axis established by the journals 23.-

An electric switch 25 is mounted within the cup-shaped member 2 upon the bottom thereof. The switch 25 is -a conventional snap switch and comprises a resiliently impelled actuating arm 26. The switch 25 may be connected in a suitable control circuit (not shown) by means of conductors 27 and 28 which extend through the bottom of the member 2.

The end portion of the actuating arm 26 of switch 25 resiliently bears upon the lower portion of one of the clevises 24 and the resilient pressure of said arm is sufficient to rock the ring 22 a clockwise direction about the journals 23, as viewed in Fig. 1, when shaft 8 is stationary or when it rotates below a predetermined rate of speed. Of course, in order to rock the ring 22 and rotor 11 to the position shown in Fig. 1, the resilient rotor 11 is deformed and the disc 20 is disposed non-symmetrically within the space 19.

Hence, when shaft 8 rotates, rotor 11 rotates with said shaft but is continuously canted under the influence of the actuating arm 26. In thus continuously can-ting the rotor 11, disc 20 which remains at right-angles to shaft 1 8 is reacted upon by the liquid 21, the reaction exerting a force upon the rotor 11 tending to move it to a symmetrical position with respect to the disc 20. This reactive force'is proportional to the rate of rotation of shaft 3 and, hence, when a predetermined minimum speed of rotation is reached by shaft 8, the reactive force of the liquid upon the disc 11 reaches a magnitude suflicient to overcome the thrust of arm 26. When this critical speed is reached, the rotor 11 moves to a symmetrical position with respect to disc 20 and actuating arm 26 is depressed whereby the position of switch 25 is changed. Thus, when shaft 8 i stationary or rotates below the critical speed, the switch 25 assumes a predetermined position, but when the shaft speed exceeds said critical speed the switch assumes a different position. In this fashion the external circuit may be controlled in response to predetermined rotary speeds of shaft 8.

In view of the fact that the reactive force of the liquid 21 upon disc 20 is a function of the viscosity or shear strength of the liquid, the critical speed at which the dev vice acts may be controlled by employing a liquid of desired viscosity or shear strength. Of course,-the strength of the resilient impelling force of switch arm 26 may also be changed to control the critical operation of the device. Referring particularly to Figs. to 8, inclusive, 29 indicates .a housing comprising a cylindrical wall portion 30, a top closure 31 and a bottom closure 32. The bottom closure 32 is provided with an internally threaded re cess 33 and an upwardly extending boss 34 is carried j by the top closure 31. A shaft 35 is journaled in the top and bottom closures which may be connected .to the spaced ends of a conventional speedometer cable (not shown), the cable sheath (not shown) being coupled to the threaded portions of the top and bottom closures.

A rotor 11' similar to rotor 11, hereinbefore described,

- is carried upon shaft 35 within the housing 29 and a disc 20', similar to disc 20, is also carriedupon said shaft 29, said switch having a resiliently impelled actuating arm 1 26" similar to actuating arm 26 of switch 25.

As a feature of the form of the invention illustrated in Figs. 5 to 8 inclusive, a bracket 36 is rigidly secured to the bottom 32 of the housing 29. The bracket 36 at its opposite ends carries upstanding lugs 37. A U-shaped member 38 is pivoted at its opposite ends upon the lugs 36 and is swingable about the pivot points 39. The U- shaped member 38 comprises a relatively fiat portion 40 which is adapted to be interposed between the upper end portion of the actuating arm 26' and the annular clamp 18 which is secured to the rotor 11. Buttons 41 are carried upon the upper and lower faces of the fiat portion 4t? of the U-shaped member 38, said buttons being centrally disposed upon the U-shaped member 38 and being interposed between the clamp 18' and the actuating arm 26.

In use, when the shaft is stationary or rotates at a speed below a predetermined minimum speed, the resiliently impelled actuating arm 26' of switch 25' bears upon the lower button 41 thereby tending to rock the U-shaped member 38 about the pivot points 39 in a clockwise direction as viewed in Figs. 5 and 6. The upper button 21 thus resiliently bears upon the lower surface of the clamp 18'. The resilient force of the actuating arm 26' is suflicient to deform rotor 11' and cant said rotor in the manner illustrated in Fig. 5. When the actuating arm 26 is in this position, the switch arm 25 is in a predetermined position. When, however, the shaft 35 rotates at a speed above said predetermined minimum speed, the reaction of the liquid 21 upon the disc 20' exerts a force upon the rotor 11' which opposes the force of the actuating arm 26' and hence the rotor 11 moves into a symmetrical position with respect to the disc 20'. When the rotor so moves, the actuating arm 26 is depressed and the switch 25 is actuated from its original position.

The switch 25 may be connected to an external control circuit (not shown) by means of conductors 27' and 28.

It will be noted that when the shaft 35 rotates thereby rotating the rotor 11 the clamp 18 slides upon the upper button 41. The material comprising the upper button 41 is preferably a soft metallic material whereby friction is reduced to a minimum. By interposing the U-shaped member 38 between the rotating rotor 11' and the actuating arm 26, erratic operation of the switch is eliminated.

It is to be understood that in both forms of the invention the switches employed may be either closed when the shaft is stationary or rotates at a speed below a predetermined speed, and may open when the shaft moves at a speed higher than said predetermined speed or the switch may be open when the shaft is stationary or rotates at a speed below a predetermined speed and is closed when the shaft rotates at a speed above said predetermined speed. Thus, the device embodying the concepts of the present invention may be employed to either open or close an electrical control circuit in response to the rotary speed of a rotating body.

I claim as my invention:

1. A device which is operably responsive to the rotary speed of a body to actuate an electric switch which comprises, a rotatable body, a rotor constructed of resilient material mounted upon said rotatable body,'said rotor having .a hollow interior for holding a liquid, a disc mounted upon said rotatable body and extending radially into said liquid in said hollow rotor, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, said actuating arm being so disposed with respect to said rotor as to exert a resilient force upon said rotor to deform said rotor and cant/ the same laterally when said rotor is stationar' said liquid reacting upon said disc within said rotor to exerta lateral force upon said rotor in opposition to the force of said actuating arm when said rotor rotates above a predetermined speed to displace said arm and actuate said switch.

2. A device which is operably responsive to the rotary speed of a body to actuate an electric switch which comprises, a rotatable body, a rotor constructed of resilient material mounted upon said rotatable body, said rotor having an annular hollow interior for holding a liquid, a disc mounted upon said rotatable body and extending radially into said liquid in said annular hollow space of said rotor, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, said actuating arm being so disposed with respect to said rotor as to exert a resilient lateral force upon said rotor to deform said rotor and cant the same laterally when said rotor is stationary, said liquid reacting upon said disc within said rotor to exert a lateral force upon said rotor in opposition to the force of said actuating arm when said rotor rotates above a predetermined speed to displace said arm and actuate said switch.

3. A device which is operably responsive to the rotary speed of a shaft to actuate an electric switch which comprises, a rotatable shaft, a rotor constructed of resilient material mounted upon said rotatable shaft, said rotor having an annular hollow interior having an axial plane generally at right-angles to said shaft for holding a liquid, a disc mounted upon said rotatable shaft with its plane substantially at right-angles to said shaft and extending radially and substantially symmetrically into said liquid in said annular hollow rotor, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, said actuating arm being so disposed with respect to said rotor as to exert a lateral resilient force upon said rotor to deform said rotor and cant the same to an unsymmetrical position with respect to said disc when said rotor is stationary, said liquid reacting upon said disc within said rotor to exert a lateral force upon said rotor to restore it to its symmetrical position with respect to said disc and in opposition to the force of said actuating arm when said rotor rotates above a predetermined speed to displace said arm and actuate said switch.

4. A device which is operably responsive to the rotary speed of a body to actuate an electric switch which comprises, a rotatable body, a rotor constructed of resilient material mounted upon said rotatable body, said rotor comprising two mating half portions, an annular clamp securing the outer peripheries of said half portions together to provide a hollow annular closed space within said rotor for holding a liquid, a substantially rigid disc mounted upon said rotatable body and extending radially at substantially right-angles to said rotatable body into said liquid in said space, a ring circumscribing said rotor and spaced radially outwardly from the periphery of said rotor, means for journalling said ring about an axis at right-angles to the axis of rotation of said rotor, clevises loosely embracing said ring on diametrically opposite positions thereof, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, said actuating arm bearing upon one of said clevises to exert a resilient force upon said clevis to rock the clevis, and ring about said journals and deform said rotor and cant the same when said body is stationary, said liquid reacting upon said disc within said rotor to exert a lateral force upon said rotor in opposition to the force of the actuating arm when said rotor rotates above a predetermined speed to move said actuating arm and actuate said switch.

5. A device which is operably responsive to the rotary speed of a body to actuate an electric switch which comprises, a casing, a rotatable body journaled for rotation in said casing, a rotor constructed of resilient material mounted upon said rotatable body, said rotor comprising two mating half portions, an annular clamp securing the outer peripheries of said half portions together to provide a hollow annular closed space with said rotor for holding a liquid, a substantially rigid disc mounted upon said rotatable body and extending radially into said liquid in said hollow rotor, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, a bracket carried by said casing, a swingable arm pivotally mounted upon said bracket and interposed between said actuating arm and said annular clamp, said actuating arm being so disposed with respect to said swingable arm and said rotor clamp as to exert a resilient force upon said swingable arm and rotor clamp so as to deform said rotor and cant the same when said rotor is stationary, said liquid reacting upon said disc within said rotor to exert a lateral force upon said rotor in opposition to the force of said actuating arm when said rotor rotates above a predetermined speed to displace said arm and actuate said switch.

6. A device which is operably responsive to the rotary speed of a body to actuate an electric switch which comprises, a casing, a rotatable body journaled for rotation in said casing, a rotor constructed of resilient material mounted upon said rotatable body, said rotor comprising two mating half portions, an annular clamp securing the outer peripheries of said half portions together to provide a hollow annular closed space with said rotor for holding a liquid, a substantially rigid disc mounted upon said rotatable body and extending radially into said liquid in said hollow rotor, an electric switch positioned adjacent said rotor, a resiliently impelled actuating arm carried by said switch to actuate said switch when said arm is moved, a bracket carried by said casing, a swingable arm pivotally mounted upon said bracket and interposed between said actuating arm and said annular clamp, said actuating arm being so disposed with respect to said swingable arm and said rotor clamp as to exert a resilient force upon said swingable arm and rotor clamp so as to deform said rotor and cant the same when said rotor is stationary, said liquid reacting upon said disc within said rotor to exert a lateral force upon said rotor in opposition to the force of said actuating arm when said rotor rotates above a predetermined speed to displace said arm and actuate said switch and bearing means carried by said swingable arm against which said rotor clamp slides during rotation of said rotor.

No references cited. 

